shell_cmds/chroot/chroot.c

   1 /*
   2  * Copyright (c) 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <sys/cdefs.h>
  35 #ifndef lint
  36 __COPYRIGHT("@(#) Copyright (c) 1988, 1993\n\
  37         The Regents of the University of California.  All rights reserved.\n");
  38 #endif /* not lint */
  39
  40 #ifndef lint
  41 #if 0
  42 static char sccsid[] = "@(#)chroot.c    8.1 (Berkeley) 6/9/93";
  43 #else
  44 __RCSID("$NetBSD: chroot.c,v 1.7 1998/10/06 03:47:51 mrg Exp $");
  45 #endif
  46 #endif /* not lint */
  47
  48 #include <sys/param.h>
  49
  50 #include <ctype.h>
  51 #include <err.h>
  52 #include <errno.h>
  53 #include <grp.h>
  54 #include <paths.h>
  55 #include <pwd.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59 #include <unistd.h>
  60
  61 int     main __P((int, char **));
  62 void    usage __P((void)) __attribute__((__noreturn__));
  63
  64 char    *user;          /* user to switch to before running program */
  65 char    *group;         /* group to switch to ... */
  66 char    *grouplist;     /* group list to switch to ... */
  67
  68 int
  69 main(argc, argv)
  70         int argc;
  71         char *argv[];
  72 {
  73         struct group *gp;
  74         struct passwd *pw;
  75         char *shell, *endp, *comma;
  76         gid_t gid = 0, gidlist[NGROUPS_MAX];
  77         uid_t uid = 0;
  78         int ch, gids;
  79
  80         while ((ch = getopt(argc, argv, "G:g:u:")) != -1)
  81                 switch(ch) {
  82                 case 'u':
  83                         user = optarg;
  84                         break;
  85                 case 'g':
  86                         group = optarg;
  87                         break;
  88                 case 'G':
  89                         grouplist = optarg;
  90                         break;
  91                 case '?':
  92                 default:
  93                         usage();
  94                 }
  95         argc -= optind;
  96         argv += optind;
  97
  98         if (argc < 1)
  99                 usage();
 100
 101         if (group) {
 102                 if (isdigit(*group)) {
 103                         gid = (gid_t)strtol(group, &endp, 0);
 104                         if (endp == group)
 105                                 goto getgroup;
 106                 } else {
 107 getgroup:
 108                         if ((gp = getgrnam(group)))
 109                                 gid = gp->gr_gid;
 110                         else
 111                                 errx(1, "no such group %s", group);
 112                 }
 113         }
 114
 115         for (gids = 0; grouplist; ) {
 116                 comma = strchr(grouplist, ',');
 117
 118                 if (comma)
 119                         *comma++ = '\0';
 120
 121                 if (isdigit(*grouplist)) {
 122                         gidlist[gids] = (gid_t)strtol(grouplist, &endp, 0);
 123                         if (endp == grouplist)
 124                                 goto getglist;
 125                 } else {
 126 getglist:
 127                         if ((gp = getgrnam(grouplist)))
 128                                 gidlist[gids] = gp->gr_gid;
 129                         else
 130                                 errx(1, "no such group %s", group);
 131                 }
 132                 gids++;
 133                 grouplist = comma;
 134         }
 135
 136         if (user) {
 137                 if (isdigit(*user)) {
 138                         uid = (uid_t)strtol(user, &endp, 0);
 139                         if (endp == user)
 140                                 goto getuser;
 141                 } else {
 142 getuser:
 143                         if ((pw = getpwnam(user)))
 144                                 uid = pw->pw_uid;
 145                         else
 146                                 errx(1, "no such user %s", user);
 147                 }
 148         }
 149
 150         if (chdir(argv[0]) || chroot("."))
 151                 err(1, "%s", argv[0]);
 152
 153         if (gids && setgroups(gids, gidlist) < 0)
 154                 err(1, "setgroups");
 155         if (group && setgid(gid) < 0)
 156                 err(1, "setgid");
 157         if (user && setuid(uid) < 0)
 158                 err(1, "setuid");
 159
 160         if (argv[1]) {
 161                 execvp(argv[1], &argv[1]);
 162                 err(1, "%s", argv[1]);
 163         }
 164
 165         if (!(shell = getenv("SHELL")))
 166                 shell = _PATH_BSHELL;
 167         execlp(shell, shell, "-i", NULL);
 168         err(1, "%s", shell);
 169         /* NOTREACHED */
 170 }
 171
 172 void
 173 usage()
 174 {
 175         (void)fprintf(stderr, "usage: chroot [-g group] [-G group,group,...] "
 176             "[-u user] newroot [command]\n");
 177         exit(1);
 178 }